Assembling several ICs required by a system in a single package is now a common practice for complex electronic systems, and is often referred to as a SIP (System In Package). Using a SIP assembly results in improved performance, less cost, and reduced size or dimension of an electronic system. Early SIP technology was based on wire bond structure or chips. However, as the number of different ICs in an electronic system increased or became more complex, the large number of wire bonds is almost unmanageable, and, making hundreds of closely spaced wire bond connections is very difficult. Furthermore, such complex wire bond arrangements are prone to breaks and/or shorts between wire bonds.
The prior art FIG. 1 is an actual photograph showing the resulting complexity of wire bonding or connecting two stacked wire bond chips to a support substrate or connection surface. Consequently, more and more ICs are being manufactured as FC's (flip chips) to help simplify the connections of a SIP. However, WB (wire bond) IC chips are still economically appropriate for many uses. Further, the cost of designing and manufacturing a FC, having the circuits that are already available on a WB type chip may not be economically worthwhile in many situations. Therefore, as SIP complexity increases, it would be advantageous if existing WB chips could be combined with available FC circuits. Furthermore, even FC interconnecting technology has become difficult.
Therefore, effective techniques for interconnecting large numbers of ICs in a SIP structure with minimal wire bonds would be advantageous.